// Copyright (c) Microsoft Corporation.
// Licensed under the MIT license.

#include "pch.h"
#include <argb.h>
#include "CascadiaSettings.h"
#include "AppKeyBindingsSerialization.h"
#include "../../types/inc/utils.hpp"
#include <appmodel.h>
#include <shlobj.h>

using namespace ::TerminalApp;
using namespace winrt::Microsoft::Terminal::TerminalControl;
using namespace winrt::TerminalApp;
using namespace winrt::Windows::Data::Json;
using namespace winrt::Windows::Storage;
using namespace winrt::Windows::Storage::Streams;
using namespace ::Microsoft::Console;

static constexpr std::wstring_view FILENAME{ L"profiles.json" };
static constexpr std::wstring_view SETTINGS_FOLDER_NAME{ L"\\Microsoft\\Windows Terminal\\" };

static constexpr std::string_view ProfilesKey{ "profiles" };
static constexpr std::string_view KeybindingsKey{ "keybindings" };
static constexpr std::string_view GlobalsKey{ "globals" };
static constexpr std::string_view SchemesKey{ "schemes" };

// Method Description:
// - Creates a CascadiaSettings from whatever's saved on disk, or instantiates
//      a new one with the default values. If we're running as a packaged app,
//      it will load the settings from our packaged localappdata. If we're
//      running as an unpackaged application, it will read it from the path
//      we've set under localappdata.
// Arguments:
// - saveOnLoad: If true, we'll write the settings back out after we load them,
//   to make sure the schema is updated.
// Return Value:
// - a unique_ptr containing a new CascadiaSettings object.
std::unique_ptr<CascadiaSettings> CascadiaSettings::LoadAll(const bool saveOnLoad)
{
    std::unique_ptr<CascadiaSettings> resultPtr;
    std::optional<std::string> fileData = _IsPackaged() ?
                                              _LoadAsPackagedApp() :
                                              _LoadAsUnpackagedApp();

    const bool foundFile = fileData.has_value();
    if (foundFile)
    {
        const auto actualData = fileData.value();

        // Parse the json data.
        Json::Value root;
        std::unique_ptr<Json::CharReader> reader{ Json::CharReaderBuilder::CharReaderBuilder().newCharReader() };
        std::string errs; // This string will recieve any error text from failing to parse.
        // `parse` will return false if it fails.
        if (!reader->parse(actualData.c_str(), actualData.c_str() + actualData.size(), &root, &errs))
        {
            // TODO:GH#990 display this exception text to the user, in a
            //      copy-pasteable way.
            throw winrt::hresult_error(WEB_E_INVALID_JSON_STRING, winrt::to_hstring(errs));
        }
        resultPtr = FromJson(root);

        if (saveOnLoad)
        {
            // Logically compare the json we've parsed from the file to what
            // we'd serialize at runtime. If the values are different, then
            // write the updated schema back out.
            const Json::Value reserialized = resultPtr->ToJson();
            if (reserialized != root)
            {
                resultPtr->SaveAll();
            }
        }
    }
    else
    {
        resultPtr = std::make_unique<CascadiaSettings>();
        resultPtr->CreateDefaults();

        // The settings file does not exist. Let's commit one.
        resultPtr->SaveAll();
    }

    return resultPtr;
}

// Method Description:
// - Serialize this settings structure, and save it to a file. The location of
//      the file changes depending whether we're running as a packaged
//      application or not.
// Arguments:
// - <none>
// Return Value:
// - <none>
void CascadiaSettings::SaveAll() const
{
    const auto json = ToJson();
    Json::StreamWriterBuilder wbuilder;
    // Use 4 spaces to indent instead of \t
    wbuilder.settings_["indentation"] = "    ";
    const auto serializedString = Json::writeString(wbuilder, json);

    if (_IsPackaged())
    {
        _SaveAsPackagedApp(serializedString);
    }
    else
    {
        _SaveAsUnpackagedApp(serializedString);
    }
}

// Method Description:
// - Serialize this object to a JsonObject.
// Arguments:
// - <none>
// Return Value:
// - a JsonObject which is an equivalent serialization of this object.
Json::Value CascadiaSettings::ToJson() const
{
    Json::Value root;

    Json::Value profilesArray;
    for (const auto& profile : _profiles)
    {
        profilesArray.append(profile.ToJson());
    }

    Json::Value schemesArray;
    const auto& colorSchemes = _globals.GetColorSchemes();
    for (auto& scheme : colorSchemes)
    {
        schemesArray.append(scheme.ToJson());
    }

    root[GlobalsKey.data()] = _globals.ToJson();
    root[ProfilesKey.data()] = profilesArray;
    root[SchemesKey.data()] = schemesArray;

    return root;
}

// Method Description:
// - Create a new instance of this class from a serialized JsonObject.
// Arguments:
// - json: an object which should be a serialization of a CascadiaSettings object.
// Return Value:
// - a new CascadiaSettings instance created from the values in `json`
std::unique_ptr<CascadiaSettings> CascadiaSettings::FromJson(const Json::Value& json)
{
    std::unique_ptr<CascadiaSettings> resultPtr = std::make_unique<CascadiaSettings>();

    if (auto globals{ json[GlobalsKey.data()] })
    {
        if (globals.isObject())
        {
            resultPtr->_globals = GlobalAppSettings::FromJson(globals);
        }
    }
    else
    {
        // If there's no globals key in the root object, then try looking at the
        // root object for those properties instead, to gracefully upgrade.
        // This will attempt to do the legacy keybindings loading too
        resultPtr->_globals = GlobalAppSettings::FromJson(json);

        // If we didn't find keybindings in the legacy path, then they probably
        // don't exist in the file. Create the default keybindings if we
        // couldn't find any keybindings.
        auto keybindings{ json[KeybindingsKey.data()] };
        if (!keybindings)
        {
            resultPtr->_CreateDefaultKeybindings();
        }
    }

    // TODO:MSFT:20737698 - Display an error if we failed to parse settings
    // What should we do here if these keys aren't found?For default profile,
    //      we could always pick the first  profile and just set that as the default.
    // Finding no schemes is probably fine, unless of course one profile
    //      references a scheme.  We could fail with come error saying the
    //      profiles file is corrupted.
    // Not having any profiles is also bad - should we say the file is corrupted?
    //      Or should we just recreate the default profiles?

    auto& resultSchemes = resultPtr->_globals.GetColorSchemes();
    if (auto schemes{ json[SchemesKey.data()] })
    {
        for (auto schemeJson : schemes)
        {
            if (schemeJson.isObject())
            {
                auto scheme = ColorScheme::FromJson(schemeJson);
                resultSchemes.emplace_back(std::move(scheme));
            }
        }
    }

    if (auto profiles{ json[ProfilesKey.data()] })
    {
        for (auto profileJson : profiles)
        {
            if (profileJson.isObject())
            {
                auto profile = Profile::FromJson(profileJson);
                resultPtr->_profiles.emplace_back(profile);
            }
        }
    }

    return resultPtr;
}

// Function Description:
// - Returns true if we're running in a packaged context. If we are, then we
//      have to use the Windows.Storage API's to save/load our files. If we're
//      not, then we won't be able to use those API's.
// Arguments:
// - <none>
// Return Value:
// - true iff we're running in a packaged context.
bool CascadiaSettings::_IsPackaged()
{
    UINT32 length = 0;
    LONG rc = GetCurrentPackageFullName(&length, NULL);
    return rc != APPMODEL_ERROR_NO_PACKAGE;
}

// Method Description:
// - Writes the given content to our settings file as UTF-8 encoded using the Windows.Storage
//      APIS's. This will only work within the context of an application with
//      package identity, so make sure to call _IsPackaged before calling this method.
//   Will overwrite any existing content in the file.
// Arguments:
// - content: the given string of content to write to the file.
// Return Value:
// - <none>
void CascadiaSettings::_SaveAsPackagedApp(const std::string& content)
{
    auto curr = ApplicationData::Current();
    auto folder = curr.RoamingFolder();

    auto file_async = folder.CreateFileAsync(FILENAME,
                                             CreationCollisionOption::ReplaceExisting);

    auto file = file_async.get();

    DataWriter dw = DataWriter();
    const char* firstChar = content.c_str();
    const char* lastChar = firstChar + content.size();

    const uint8_t* firstByte = reinterpret_cast<const uint8_t*>(firstChar);
    const uint8_t* lastByte = reinterpret_cast<const uint8_t*>(lastChar);
    winrt::array_view<const uint8_t> bytes{ firstByte, lastByte };
    dw.WriteBytes(bytes);

    FileIO::WriteBufferAsync(file, dw.DetachBuffer()).get();
}

// Method Description:
// - Writes the given content in UTF-8 to our settings file using the Win32 APIS's.
//   Will overwrite any existing content in the file.
// Arguments:
// - content: the given string of content to write to the file.
// Return Value:
// - <none>
//   This can throw an exception if we fail to open the file for writing, or we
//      fail to write the file
void CascadiaSettings::_SaveAsUnpackagedApp(const std::string& content)
{
    // Get path to output file
    // In this scenario, the settings file will end up under e.g. C:\Users\admin\AppData\Roaming\Microsoft\Windows Terminal\profiles.json
    std::wstring pathToSettingsFile = CascadiaSettings::_GetFullPathToUnpackagedSettingsFile();

    auto hOut = CreateFileW(pathToSettingsFile.c_str(), GENERIC_WRITE, 0, NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
    if (hOut == INVALID_HANDLE_VALUE)
    {
        THROW_LAST_ERROR();
    }
    THROW_LAST_ERROR_IF(!WriteFile(hOut, content.c_str(), gsl::narrow<DWORD>(content.length()), 0, 0));
    CloseHandle(hOut);
}

// Method Description:
// - Computes the path to the settings file if the app is run unpackaged.
//   Will create any intermediate directories if they don't exist.
//   The file will end up under e.g. C:\Users\admin\AppData\Roaming\Microsoft\Windows Terminal\profiles.json
// Arguments:
// - <none>
// Return Value:
// - A string containing the path to the unpackaged settings file
//   This can throw an exception if it fails to get the roaming app data folder.
std::wstring CascadiaSettings::_GetFullPathToUnpackagedSettingsFile()
{
    wil::unique_cotaskmem_string roamingAppDataFolder;
    if (FAILED(SHGetKnownFolderPath(FOLDERID_RoamingAppData, 0, 0, &roamingAppDataFolder)))
    {
        THROW_LAST_ERROR();
    }

    std::wstring parentDirectoryForSettingsFile(roamingAppDataFolder.get());
    parentDirectoryForSettingsFile.append(SETTINGS_FOLDER_NAME);

    // Create the directory if it doesn't exist
    wil::CreateDirectoryDeep(parentDirectoryForSettingsFile.c_str());

    std::wstring pathToSettingsFile(parentDirectoryForSettingsFile);
    pathToSettingsFile.append(FILENAME);

    return pathToSettingsFile;
}

// Method Description:
// - Reads the content of our settings file using the Windows.Storage
//      APIS's. This will only work within the context of an application with
//      package identity, so make sure to call _IsPackaged before calling this method.
// Arguments:
// - <none>
// Return Value:
// - an optional with the content of the file if we were able to open it,
//      otherwise the optional will be empty
std::optional<std::string> CascadiaSettings::_LoadAsPackagedApp()
{
    auto curr = ApplicationData::Current();
    auto folder = curr.RoamingFolder();
    auto file_async = folder.TryGetItemAsync(FILENAME);
    auto file = file_async.get();

    if (file == nullptr)
    {
        return std::nullopt;
    }
    const auto storageFile = file.as<StorageFile>();

    // settings file is UTF-8 without BOM
    auto buffer = FileIO::ReadBufferAsync(storageFile).get();
    auto bufferData = buffer.data();
    std::vector<uint8_t> bytes{ bufferData, bufferData + buffer.Length() };
    std::string resultString{ bytes.begin(), bytes.end() };
    return { resultString };
}

// Method Description:
// - Reads the content in UTF-8 enconding of our settings file using the Win32 APIs
// Arguments:
// - <none>
// Return Value:
// - an optional with the content of the file if we were able to open it,
//      otherwise the optional will be empty.
//   If the file exists, but we fail to read it, this can throw an exception
//      from reading the file
std::optional<std::string> CascadiaSettings::_LoadAsUnpackagedApp()
{
    std::wstring pathToSettingsFile = CascadiaSettings::_GetFullPathToUnpackagedSettingsFile();
    const auto hFile = CreateFileW(pathToSettingsFile.c_str(), GENERIC_READ, 0, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
    if (hFile == INVALID_HANDLE_VALUE)
    {
        // If the file doesn't exist, that's fine. Just log the error and return
        //      nullopt - we'll create the defaults.
        LOG_LAST_ERROR();
        return std::nullopt;
    }

    // fileSize is in bytes
    const auto fileSize = GetFileSize(hFile, nullptr);
    THROW_LAST_ERROR_IF(fileSize == INVALID_FILE_SIZE);

    auto utf8buffer = std::make_unique<char[]>(fileSize);

    DWORD bytesRead = 0;
    THROW_LAST_ERROR_IF(!ReadFile(hFile, utf8buffer.get(), fileSize, &bytesRead, nullptr));
    CloseHandle(hFile);

    // convert buffer to UTF-8 string
    std::string utf8string(utf8buffer.get(), fileSize);

    return { utf8string };
}

// function Description:
// - Returns the full path to the settings file, either within the application
//   package, or in its unpackaged location.
// Arguments:
// - <none>
// Return Value:
// - the full path to the settings file
winrt::hstring CascadiaSettings::GetSettingsPath()
{
    return _IsPackaged() ? CascadiaSettings::_GetPackagedSettingsPath() :
                           winrt::hstring{ CascadiaSettings::_GetFullPathToUnpackagedSettingsFile() };
}

// Function Description:
// - Get the full path to settings file in its packaged location.
// Arguments:
// - <none>
// Return Value:
// - the full path to the packaged settings file.
winrt::hstring CascadiaSettings::_GetPackagedSettingsPath()
{
    const auto curr = ApplicationData::Current();
    const auto folder = curr.RoamingFolder();
    const auto file_async = folder.TryGetItemAsync(FILENAME);
    const auto file = file_async.get();
    return file.Path();
}